By shining a tightly focused laser light on the condensate and moving the center of the beam along the spiral line one may stir the condensate and create vortices. It is shown that one can induce rotation of the condensate in the direction opposite to the direction of the stirring.
@article{arxiv.cond-mat/0205478,
title = {Stirring Bose-Einstein condensate},
author = {Bogdan Damski and Krzysztof Sacha and Jakub Zakrzewski},
journal= {arXiv preprint arXiv:cond-mat/0205478},
year = {2009}
}